lec02_Computer_Performance

lec02_Computer_Performance - Lecture 2: Computer...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 2: Computer Performance Computer Architecture Csc 205
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Reminders ° Office hours from 12:00 to 1:00 on Tuesday and Thursday in PL324 ° Course web page at http://www.cse.lehigh.edu/~mschulte/ece201-02 ° Download copies of Course Syllabus and Course Schedule ° Finish reading Chapters 1 and 2 by next class period. ° Fill out the Course Survey (Assignment 0)
Background image of page 2
Performance and Cost ° Purchasing perspective given a collection of machines, which has the - best performance ? - least cost ? - best performance / cost ? ° Design perspective faced with design options, which has the - best performance improvement ? - least cost ? - best performance / cost ? ° Both require basis for comparison metric for evaluation ° Our goal is to understand cost & performance implications of architectural choices
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Two notions of “performance” ° Time to do the task (Execution Time) – execution time, response time, latency ° Tasks per day, hour, week, sec, ns. . . (Performance) – performance, throughput, bandwidth Response time and throughput often are in opposition - why? Plane Boeing 747 BAD/Sud Concodre Speed 610 mph 1350 mph DC to Paris 6.5 hours 3 hours Passengers 470 132 Throughput (pmph) 286,700 178,200 Which has higher performance?
Background image of page 4
Performance Definitions ° Performance is in units of things-per-second bigger is better ° If we are primarily concerned with response time performance(x) = 1 execution_time(x) ° " X is n times faster than Y" means performance(X) execution_time(Y) n = ---------------------- = ---------------------- performance(Y) execution_time(X) ° When is throughput more important than execution time? ° When is execution time more important than throughput?
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Peformance Examples Time of Concorde vs. Boeing 747? Concord is 1350 mph / 610 mph = 2.2 times faster = 6.5 hours / 3 hours Throughput of Concorde vs. Boeing 747 ? Concord is 178,200 pmph / 286,700 pmph = 0.62 “times faster” Boeing is 286,700 pmph / 178,200 pmph = 1.6 “times faster” Boeing is 1.6 times (“60%”) faster in terms of throughput Concord is 2.2 times (“120%”) faster in terms of flying time When discussing processor performance, we will focus primarily on execution time for a single job - why?
Background image of page 6
° How are the following likely to effect response time and throughput? Increasing the clock speed of a given processor. Increasing the number of jobs in a system (e.g., having a single computer service multiple users). Increasing the number of processors in a sytem that uses multiple processors (e.g., a network of ATM machines). ° If an Pentium III runs a program in 8 seconds and a PowerPC runs the same program in 10 seconds, how many times faster is the Pentium Pro? n =
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 25

lec02_Computer_Performance - Lecture 2: Computer...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online